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Yan X, Huang S, Li H, Feng Z, Kong J, Liu J. The causal effect of mTORC1-dependent circulating protein levels on nonalcoholic fatty liver disease: A Mendelian randomization study. Dig Liver Dis 2024; 56:559-564. [PMID: 37778897 DOI: 10.1016/j.dld.2023.09.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 08/24/2023] [Accepted: 09/19/2023] [Indexed: 10/03/2023]
Abstract
BACKGROUND The mechanistic target of rapamycin (mTOR) signal pathway plays a crucial role in the development of nonalcoholic fatty liver disease (NAFLD). However, the causal effect of mTOR downstream proteins on NAFLD remains unknown. AIMS We conducted a two-sample Mendelian randomization (MR) study to investigate whether the mTOR-dependent circulating proteins, including Eukaryotic Initiation Factor 4E Binding Proteins (eIF4EBPs), Ribosomal Protein S6K kinase 1 (RP-S6K), Eukaryotic Initiation Factor 4E (eIF4E), Eukaryotic Initiation Factor 4A (eIF4A) and Eukaryotic Initiation Factor 4 G (eIF4G), have causal effects on the risk of NAFLD. METHODS The causal estimate was evaluated with the inverse-variance weighted (IVW) method in discovery stage and validation stage. The single-nucleotide polymorphisms (SNPs) were selected to genetically predict exposures from Genome-Wide Association Studies (GWAS). Exposures with statistically significant effects in the discovery dataset would be further validated in the validation dataset. RESULTS MR study revealed that eIF4E had a causal effect on NAFLD in both discovery stage (OR = 1.339, P = 0.037) and validation stage (OR = 1.0007, P = 0.022). Sensitivity analyses confirmed robustness of the results. CONCLUSION The genetically predicted higher level of mTOR-dependent eIF4E in plasma might have a causal effect on the occurrence of NAFLD.
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Affiliation(s)
- Xiangyu Yan
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, China
| | - Songhan Huang
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, China
| | - Hongxin Li
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, China
| | - Zichen Feng
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, China
| | - Junjie Kong
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, China; Department of hepatobiliary surgery, Shandong Provincial Hospital affiliated to Shandong first medical university, Jinan, Shandong 250021, China
| | - Jun Liu
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, China; Department of hepatobiliary surgery, Shandong Provincial Hospital affiliated to Shandong first medical university, Jinan, Shandong 250021, China.
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Effects of co-administration of rapamycin and evening primrose/hemp seed oil supplement on immunologic factors and cell membrane fatty acids in experimental autoimmune encephalomyelitis. Gene 2020; 759:144987. [PMID: 32712065 DOI: 10.1016/j.gene.2020.144987] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 06/29/2020] [Accepted: 07/17/2020] [Indexed: 01/09/2023]
Abstract
BACKGROUND The immune response is influenced by the administration of omega-3 polyunsaturated fatty acids (PUFA). Multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE) are affected by PUFA. The combination of evening primrose/hemp seed oil (EPO/HSO) has essential fatty acids (EFAs) for human optimal health due to the favorable ratio of omega-6/omega-3 and antioxidantal properties. The study was conducted to evaluate the effects of EPO/HSO on improving the membrane fatty acids composition of spleen and blood cells and immunologic factors in compared to rapamycin (RAPA) in the EAE model. METHODS AND MATERIALS Chronic-EAE was induced by induction of MOG in C57BL/6J mice (female, age: 6-8 weeks, weight 18-21). Mice were assigned to 5 groups (6/group) to evaluate the therapeutic effects of EPO/HSO supplement in comparison with rapamycin: A group; EPO/HSO + RAPA, B group; RAPA, C group; EPO/HSO. Results were compared to two control groups (EAE and naive). The fatty acid profile of the spleen and blood cell membrane was evaluated. Real-time-polymerase chain reaction was used for the evaluate the genes expression levels of interleukin (IL) -4, IL-5, and IL-13 in lymphocytes. Also, IL-4 of serum was evaluated by enzyme-linked immunosorbent assay (ELISA). RESULTS Our findings indicated that EPO/HSO therapy significantly increased the percentage of essential fatty acids in cell membrane of the spleen and blood. The relative expression of IL-4, IL-5, and IL-13 genes in lymphocytes and serum level of IL-4 was significantly increased in the HSO/EPO treated group versus other groups. CONCLUSION These results point to potential therapeutic effects on the repair of the structure of cell membranes and suppression of inflammation by EPO/HSO in EAE.
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Soliman GA, Schooling CM. Causal association between mTOR-dependent EIF-4E and EIF-4A circulating protein levels and type 2 diabetes: a Mendelian randomization study. Sci Rep 2020; 10:15737. [PMID: 32978410 PMCID: PMC7519073 DOI: 10.1038/s41598-020-71987-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 08/19/2020] [Indexed: 12/22/2022] Open
Abstract
The mammalian Target of Rapamycin complex 1 (mTORC1) nutrient-sensing pathway is a central regulator of cell growth and metabolism and is dysregulated in diabetes. The eukaryotic translation initiation factor 4E (EIF-4E) protein, a key regulator of gene translation and protein function, is controlled by mTORC1 and EIF-4E Binding Proteins (EIF4EBPs). Both EIF4EBPs and ribosomal protein S6K kinase (RP-S6K) are downstream effectors regulated by mTORC1 but converge to regulate two independent pathways. We investigated whether the risk of type 2 diabetes varied with genetically predicted EIF-4E, EIF-4A, EIF-4G, EIF4EBP, and RP-S6K circulating levels using Mendelian Randomization. We estimated the causal role of EIF-4F complex, EIF4EBP, and S6K in the circulation on type 2 diabetes, based on independent single nucleotide polymorphisms strongly associated (p = 5 × 10–6) with EIF-4E (16 SNPs), EIF-4A (11 SNPs), EIF-4G (6 SNPs), EIF4EBP2 (12 SNPs), and RP-S6K (16 SNPs). The exposure data were obtained from the INTERVAL study. We applied these SNPs for each exposure to publically available genetic associations with diabetes from the DIAbetes Genetics Replication And Meta-analysis (DIAGRAM) case (n = 26,676) and control (n = 132,532) study (mean age 57.4 years). We meta-analyzed SNP-specific Wald-estimates using inverse variance weighting with multiplicative random effects and conducted sensitivity analysis. Mendelian Randomization (MR-Base) R package was used in the analysis. The PhenoScanner curated database was used to identify disease associations with SNP gene variants. EIF-4E is associated with a lowered risk of type 2 diabetes with an odds ratio (OR) 0.94, 95% confidence interval (0.88, 0.99, p = 0.03) with similar estimates from the weighted median and MR-Egger. Similarly, EIF-4A was associated with lower risk of type 2 diabetes with odds ratio (OR) 0.90, 95% confidence interval (0.85, 0.97, p = 0.0003). Sensitivity analysis using MR-Egger and weighed median analysis does not indicate that there is a pleiotropic effect. This unbiased Mendelian Randomization estimate is consistent with a protective causal association of EIF-4E and EIF-4A on type 2 diabetes. EIF-4E and EIF-4A may be targeted for intervention by repurposing existing therapeutics to reduce the risk of type 2 diabetes.
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Affiliation(s)
- Ghada A Soliman
- Department of Environmental, Occupational and Geospatial Health Sciences, The City University of New York, Graduate School of Public Health and Health Policy, 55 West 125th St, New York, NY, 10027, USA.
| | - C Mary Schooling
- Department of Environmental, Occupational and Geospatial Health Sciences, The City University of New York, Graduate School of Public Health and Health Policy, 55 West 125th St, New York, NY, 10027, USA.,School of Public Health, Li Ka Shing, Faculty of Medicine, The University of Hong Kong, 7 Sassoon Road, Hong Kong, China
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Meal for Two: Human Cytomegalovirus-Induced Activation of Cellular Metabolism. Viruses 2019; 11:v11030273. [PMID: 30893762 PMCID: PMC6466105 DOI: 10.3390/v11030273] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 03/12/2019] [Accepted: 03/13/2019] [Indexed: 12/18/2022] Open
Abstract
Viruses are parasites that depend on the host cell’s metabolic resources to provide the energy and molecular building blocks necessary for the production of viral progeny. It has become increasingly clear that viruses extensively modulate the cellular metabolic network to support productive infection. Here, we review the numerous ways through which human cytomegalovirus (HCMV) modulates cellular metabolism, highlighting known mechanisms of HCMV-mediated metabolic manipulation and identifying key outstanding questions that remain to be addressed.
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Angiogenesis in Pancreatic Cancer: Pre-Clinical and Clinical Studies. Cancers (Basel) 2019; 11:cancers11030381. [PMID: 30889903 PMCID: PMC6468440 DOI: 10.3390/cancers11030381] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 03/11/2019] [Accepted: 03/14/2019] [Indexed: 02/06/2023] Open
Abstract
Angiogenesis is a crucial event in tumor development and progression, occurring by different mechanisms and it is driven by pro- and anti-angiogenic molecules. Pancreatic cancer vascularization is characterized by a high microvascular density, impaired microvessel integrity and poor perfused vessels with heterogeneous distribution. In this review article, after a brief introduction on pancreatic cancer classification and on angiogenesis mechanisms involved in its progression, the pre-clinical and clinical trials conducted in pancreatic cancer treatment using anti-angiogenic inhibitors will be described. Finally, we will discuss the anti-angiogenic therapy paradox between the advantage to abolish vessel supply to block tumor growth and the disadvantage due to reduction of drug delivery at the same time. The purpose is to identify new anti-angiogenic molecules that may enhance treatment regimen.
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The Human Cytomegalovirus UL38 protein drives mTOR-independent metabolic flux reprogramming by inhibiting TSC2. PLoS Pathog 2019; 15:e1007569. [PMID: 30677091 PMCID: PMC6363234 DOI: 10.1371/journal.ppat.1007569] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 02/05/2019] [Accepted: 01/07/2019] [Indexed: 12/22/2022] Open
Abstract
Human Cytomegalovirus (HCMV) infection induces several metabolic activities that are essential for viral replication. Despite the important role that this metabolic modulation plays during infection, the viral mechanisms involved are largely unclear. We find that the HCMV UL38 protein is responsible for many aspects of HCMV-mediated metabolic activation, with UL38 being necessary and sufficient to drive glycolytic activation and induce the catabolism of specific amino acids. UL38's metabolic reprogramming role is dependent on its interaction with TSC2, a tumor suppressor that inhibits mTOR signaling. Further, shRNA-mediated knockdown of TSC2 recapitulates the metabolic phenotypes associated with UL38 expression. Notably, we find that in many cases the metabolic flux activation associated with UL38 expression is largely independent of mTOR activity, as broad spectrum mTOR inhibition does not impact UL38-mediated induction of glycolysis, glutamine consumption, or the secretion of proline or alanine. In contrast, the induction of metabolite concentrations observed with UL38 expression are largely dependent on active mTOR. Collectively, our results indicate that the HCMV UL38 protein induces a pro-viral metabolic environment via inhibition of TSC2.
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Rezapour-Firouzi S, Kheradmand F, Shahabi S, Tehrani AA, Mazloomi E, Mohammadzadeh A. Regulatory effects of hemp seed/evening primrose oil supplement in comparison with rapamycin on the expression of the mammalian target of rapamycin-complex 2 and interleukin-10 genes in experimental autoimmune encephalomyelitis. Res Pharm Sci 2019; 14:36-45. [PMID: 30936931 PMCID: PMC6407336 DOI: 10.4103/1735-5362.251851] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The mammalian target of rapamycin (mTOR) signaling plays a critical role in lipid synthesis and immune responses. The T regulatory cells (Treg) as suppressor of T cells, are a subset of T cells that modulate the immune system, maintain tolerance, and prevent autoimmune diseases.. The interleukin (IL) -10 derived from the Treg and T helper (Th) 2 is an anti-inflammatory cytokine in multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). Due to the exclusive roles of rapamycin (RAPA) in mTOR inhibition, we evaluated the regulatory effect of the hemp seed oil/evening primrose oil (HSO/EPO) supplement in comparison with RAPA in EAE. EAE was induced by using myelin oligodendrocyte glycoprotein peptide and complete freund’s adjuvant (CFA) in C57BL/6 mice, total mRNA was extracted from local lymph nodes and real-time polymerase chain reaction was used to evaluate the expression level of the rapamycin-insensitive companion of mTOR complex 2 (RICTOR) and IL-10 genes. The expression of IL-10 and RICTOR genes were significantly increased in HSO/EPO group. In contrast with RAPA groups, histological findings have shown that the HSO/EPO treated group remarkably reduced cell infiltration and promoted remyelination. The EPO/HSO has beneficial effects on the repair of myelin, which was confirmed by immunological and histological findings.
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Affiliation(s)
- Soheila Rezapour-Firouzi
- Cellular and Molecular Research Center, Cellular and Molecular Medicine Institute, Urmia University of Medical Sciences, Urmia, I.R. Iran
| | - Fatemeh Kheradmand
- Solid Tumor Research Center, Urmia University of Medical sciences, Urmia, I.R. Iran
| | - Shahram Shahabi
- Cellular and Molecular Research Center, Cellular and Molecular Medicine Institute, Urmia University of Medical Sciences, Urmia, I.R. Iran
| | - Ali Asghar Tehrani
- Department of Pathobiology, Faculty of Veterinary Medicine, Urmia University, Urmia, I.R. Iran
| | - Ebrahim Mazloomi
- Cellular and Molecular Research Center, Cellular and Molecular Medicine Institute, Urmia University of Medical Sciences, Urmia, I.R. Iran
| | - Adel Mohammadzadeh
- Departement of Immunology and Genetics, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, I.R. Iran
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Arshad Z, Rezapour-Firouzi S, Mohammadian M, Ebrahimifar. The Sources of Essential Fatty Acids for Allergic and Cancer Patients; a Connection with Insight into Mammalian Target of Rapamycin: A Narrative Review. Asian Pac J Cancer Prev 2018; 19:2391-2401. [PMID: 30255691 PMCID: PMC6249470 DOI: 10.22034/apjcp.2018.19.9.2391] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Background: Disturbance in essential fatty acids (EFA) metabolism plays a key role in autoimmune diseases, but EFA supplementation with sources of borage, evening primrose, hemp seed and fish oils was not effective in atopic and cancer diseases, as that seen in the case of multiple sclerosis. It seems that two complexes of the mammalian target of rapamycin (mTOR) signaling, mTORC1 and mTORC2, are congruent with the two bases of the Traditional Iranian Medicine (TIM) therapy, Cold and Hot nature, which are essential for the efficacy of functional oils for controlling immune responses in autoimmune diseases. Methods: We searched PubMed database, Web of Science (WOS), Google Scholar, Scopus and selected studies by predefined eligibility criteria. We then assessed their quality and extracted data. Results: The oils controlled by Cold or Hot nature may be helpful in maintaining homeostasis and preventing autoimmune diseases. In summary, studies of randomized controlled trials for allergy and cancer patients found no improvement in the signs or response to tests, despite a remarkable change in EFA fractions in the blood by supplementation with sources of borage, evening primrose, hemp seed and fish oils. In contrast, portulaca oleracea oil exhibited protective effects by anti-inflammatory properties via the PI3K/Akt/mTORC2 pathway with a deviation immune response to Th1 to treat atopic diseases and cancer. Conclusions: According to the concept of Traditional Iranian Medicine therapy, in contrast to Cold-nature oils, EFA supplementation with the sources of Hot-nature oilsis not suitable for the treatment of atopic and cancerous diseases.
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Affiliation(s)
- Zhila Arshad
- Department of Pathology of Anatomy, School of Medicine, Baku University of Medical Sciences, Baku, Azerbaijan. ,
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Abstract
The common relationships among a great variety of biological phenomena seem enigmatic when considered solely at the level of the phenotype. The deep connections in physiology, for example, between the effects of maternal food restriction in utero and the subsequent incidence of metabolic syndrome in offspring, the effects of microgravity on cell polarity and reproduction in yeast, stress effects on jellyfish, and their endless longevity, or the relationship between nutrient abundance and the colonial form in slime molds, are not apparent by phenotypic observation. Yet all of these phenomena are ultimately determined by the Target of Rapamycin (TOR) gene and its associated signaling complexes. In the same manner, the unfolding of evolutionary physiology can be explained by a comparable application of the common principle of cell-cell signaling extending across complex developmental and phylogenetic traits. It is asserted that a critical set of physiologic and phenotypic adaptations emanated from a few crucial, ancestral receptor gene duplications that enabled the successful terrestrial transition of vertebrates from water to land. In combination, mTor and its cognate receptors and a few crucial genetic duplications provide a mechanistic common denominator across a diverse spectrum of biological responses. The proper understanding of their purpose yields a unified concept of physiology and its evolutionary development. © 2018 American Physiological Society. Compr Physiol 8:761-771, 2018.
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Affiliation(s)
- John S Torday
- Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, California, USA
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Jirakkakul J, Roytrakul S, Srisuksam C, Swangmaneecharern P, Kittisenachai S, Jaresitthikunchai J, Punya J, Prommeenate P, Senachak J, So L, Tachaleat A, Tanticharoen M, Cheevadhanarak S, Wattanachaisaereekul S, Amnuaykanjanasin A. Culture degeneration in conidia of Beauveria bassiana and virulence determinants by proteomics. Fungal Biol 2017; 122:156-171. [PMID: 29458719 DOI: 10.1016/j.funbio.2017.12.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 12/04/2017] [Accepted: 12/15/2017] [Indexed: 01/18/2023]
Abstract
The quality of Beauveria bassiana conidia directly affects the virulence against insects. In this study, continuous subculturing of B. bassiana on both rice grains and potato dextrose agar (PDA) resulted in 55 and 49 % conidial yield reduction after 12 passages and 68 and 60 % virulence reduction after 20 and 12 passages at four d post-inoculation, respectively. The passage through Tenebrio molitor and Spodoptera exigua restored the virulence of rice and PDA subcultures, respectively. To explore the molecular mechanisms underlying the conidial quality and the decline of virulence after multiple subculturing, we investigated the conidial proteomic changes. Successive subculturing markedly increased the protein levels in oxidative stress response, autophagy, amino acid homeostasis, and apoptosis, but decreased the protein levels in DNA repair, ribosome biogenesis, energy metabolism, and virulence. The nitro blue tetrazolium assay verified that the late subculture's colony and conidia had a higher oxidative stress level than the early subculture. A 2A-type protein phosphatase and a Pleckstrin homology domain protein Slm1, effector proteins of the target of rapamycin (TOR) complex 1 and 2, respectively, were dramatically increased in the late subculture. These results suggest that TOR signalling might be associated with ageing in B. bassiana late subculture, in turn affecting its physiological characteristics and virulence.
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Affiliation(s)
- Jiraporn Jirakkakul
- Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi (KMUTT), Bangkhuntien, Bangkok 10150, Thailand
| | - Sittiruk Roytrakul
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120, Thailand
| | - Chettida Srisuksam
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120, Thailand
| | - Pratchya Swangmaneecharern
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120, Thailand
| | - Suthathip Kittisenachai
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120, Thailand
| | - Janthima Jaresitthikunchai
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120, Thailand
| | - Juntira Punya
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120, Thailand
| | - Peerada Prommeenate
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120, Thailand
| | - Jittisak Senachak
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120, Thailand
| | - Laihong So
- Department of Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Kowloon, Hong Kong
| | - Anuwat Tachaleat
- Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi (KMUTT), Bangkhuntien, Bangkok 10150, Thailand
| | - Morakot Tanticharoen
- Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi (KMUTT), Bangkhuntien, Bangkok 10150, Thailand
| | - Supapon Cheevadhanarak
- Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi (KMUTT), Bangkhuntien, Bangkok 10150, Thailand
| | - Songsak Wattanachaisaereekul
- Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi (KMUTT), Bangkhuntien, Bangkok 10150, Thailand.
| | - Alongkorn Amnuaykanjanasin
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120, Thailand.
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Pinto-Leite R, Arantes-Rodrigues R, Sousa N, Oliveira PA, Santos L. mTOR inhibitors in urinary bladder cancer. Tumour Biol 2016; 37:11541-11551. [PMID: 27235118 DOI: 10.1007/s13277-016-5083-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 05/15/2016] [Indexed: 02/07/2023] Open
Abstract
Despite the great scientific advances that have been made in cancer treatment, there is still much to do, particularly with regard to urinary bladder cancer. Some of the drugs used in urinary bladder cancer treatment have been in use for more than 30 years and show reduced effectiveness and high recurrence rates. There have been several attempts to find new and more effective drugs, to be used alone or in combination with the drugs already in use, in order to overcome this situation.The biologically important mammalian target of rapamycin (mTOR) pathway is altered in cancer and mTOR inhibitors have raised many expectations as potentially important anticancer drugs. In this article, the authors will review the mTOR pathway and present their experiences of the use of some mTOR inhibitors, sirolimus, everolimus and temsirolimus, in isolation and in conjunction with non-mTOR inhibitors cisplatin and gemcitabine, on urinary bladder tumour cell lines. The non-muscle-invasive cell line, 5637, is the only one that exhibits a small alteration in the mTOR and AKT phosphorylation after rapalogs exposure. Also, there was a small inhibition of cell proliferation. With gemcitabine plus everolimus or temsirolimus, the results were encouraging as a more effective response was noticed with both combinations, especially in the 5637 and T24 cell lines. Cisplatin associated with everolimus or temsirolimus also gave promising results, as an antiproliferative effect was observed when the drugs were associated, in particular on the 5637 and HT1376 cell lines. Everolimus or temsirolimus in conjunction with gemcitabine or cisplatin could have an important role to play in urinary bladder cancer treatment, depending on the tumour grading.
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Affiliation(s)
- R Pinto-Leite
- Genetic Service, Cytogenetic Laboratory, Hospital Center of Trás-os-Montes and Alto Douro, Vila Real, Portugal. .,Experimental Pathology and Therapeutics Group, Portuguese Institute of Oncology, Porto, Portugal.
| | - R Arantes-Rodrigues
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.,QOPNA, Mass Spectrometry Center, Department of Chemistry, University of Aveiro, Aveiro, Portugal.,Institute for Research and Innovation in Health (I3S), Porto, Portugal
| | - Nuno Sousa
- Health School, University Fernando Pessoa, Porto, Portugal
| | - P A Oliveira
- Experimental Pathology and Therapeutics Group, Portuguese Institute of Oncology, Porto, Portugal
| | - L Santos
- Experimental Pathology and Therapeutics Group, Portuguese Institute of Oncology, Porto, Portugal.,Health School, University Fernando Pessoa, Porto, Portugal.,Medical Oncology Department, Portuguese Institute of Oncology, Porto, Portugal
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12
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Kay NE, Sassoon T, Secreto C, Sinha S, Shanafelt TD, Ghosh AK, Arbiser JL. Tris (dibenzylideneacetone) dipalladium: a small-molecule palladium complex is effective in inducing apoptosis in chronic lymphocytic leukemia B-cells. Leuk Lymphoma 2016; 57:2409-16. [PMID: 27189785 DOI: 10.3109/10428194.2016.1161186] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Here we tested impact of Tris (dibenzylideneacetone) dipalladium (Tris-DBA) on chronic lymphocytic leukemia (CLL) B-cell survival. Indeed, treatment of CLL B-cells with Tris-DBA induced apoptosis in a dose-dependent manner irrespective of IgVH mutational status. Further analyses suggest that Tris-DBA-induced apoptosis involves reduced expression of the anti-apoptotic proteins Bcl-xL, and XIAP with an upregulation of the pro-apoptotic protein BIM in CLL B-cells. Our findings also indicate that Tris-DBA targets the ribosomal protein (rp)-S6, an essential component of the Akt/mTOR signaling axis in CLL B-cells. Of interest, CLL bone marrow stromal cells were unable to protect the leukemic B cells from Tris-DBA-induced apoptosis in an in vitro co-culture system. Finally, co-administration of Tris-DBA and the purine nucleoside analog fludarabine (F-ara-A) augmented CLL B-cell apoptosis levels in vitro showing synergistic effects. In total, Tris-DBA is effective at inducing apoptosis in CLL B-cells even in the presence of stromal cells likely by targeting directly the signal mediator, rpS6.
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Affiliation(s)
- Neil E Kay
- a Division of Hematology , Mayo Clinic , Rochester , MN , USA
| | - Traci Sassoon
- a Division of Hematology , Mayo Clinic , Rochester , MN , USA
| | - Charla Secreto
- a Division of Hematology , Mayo Clinic , Rochester , MN , USA
| | - Sutapa Sinha
- a Division of Hematology , Mayo Clinic , Rochester , MN , USA
| | | | - Asish K Ghosh
- b Stephenson Cancer Center, Department of Pathology , University of Oklahoma , Oklahoma , OK , USA
| | - Jack L Arbiser
- c Department of Dermatology , Emory University, Winship Cancer Institute , Atlanta , GA , USA
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Wang F, Alain T, Szretter KJ, Stephenson K, Pol JG, Atherton MJ, Hoang HD, Fonseca BD, Zakaria C, Chen L, Rangwala Z, Hesch A, Chan ESY, Tuinman C, Suthar MS, Jiang Z, Ashkar AA, Thomas G, Kozma SC, Gale M, Fitzgerald KA, Diamond MS, Mossman K, Sonenberg N, Wan Y, Lichty BD. S6K-STING interaction regulates cytosolic DNA-mediated activation of the transcription factor IRF3. Nat Immunol 2016; 17:514-522. [PMID: 27043414 PMCID: PMC4917298 DOI: 10.1038/ni.3433] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 03/08/2016] [Indexed: 12/17/2022]
Abstract
Cytosolic DNA-mediated activation of the transcription factor IRF3 is a key event in host antiviral responses. Here we found that infection with DNA viruses induced interaction of the metabolic checkpoint kinase mTOR downstream effector and kinase S6K1 and the signaling adaptor STING in a manner dependent on the DNA sensor cGAS. We further demonstrated that the kinase domain, but not the kinase function, of S6K1 was required for the S6K1-STING interaction and that the TBK1 critically promoted this process. The formation of a tripartite S6K1-STING-TBK1 complex was necessary for the activation of IRF3, and disruption of this signaling axis impaired the early-phase expression of IRF3 target genes and the induction of T cell responses and mucosal antiviral immunity. Thus, our results have uncovered a fundamental regulatory mechanism for the activation of IRF3 in the cytosolic DNA pathway.
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Affiliation(s)
- Fuan Wang
- McMaster Immunology Research Centre, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- MG DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Tommy Alain
- Children’s Hospital of Eastern Ontario Research Institute and Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON K1H 8L1, Canada
| | - Kristy J. Szretter
- Department of Medicine, Molecular Microbiology, Pathology & Immunology, Washington, University School of Medicine, St Louis, MO 63110, United States of America
| | - Kyle Stephenson
- McMaster Immunology Research Centre, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- MG DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Jonathan G. Pol
- McMaster Immunology Research Centre, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- MG DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Matthew J. Atherton
- McMaster Immunology Research Centre, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- MG DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Huy-Dung Hoang
- Children’s Hospital of Eastern Ontario Research Institute and Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON K1H 8L1, Canada
| | - Bruno D. Fonseca
- Children’s Hospital of Eastern Ontario Research Institute and Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON K1H 8L1, Canada
| | - Chadi Zakaria
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada
| | - Lan Chen
- McMaster Immunology Research Centre, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- MG DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Zainab Rangwala
- McMaster Immunology Research Centre, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- MG DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Adam Hesch
- McMaster Immunology Research Centre, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- MG DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Eva Sin Yan Chan
- McMaster Immunology Research Centre, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- MG DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Carly Tuinman
- McMaster Immunology Research Centre, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- MG DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Mehul S. Suthar
- Department of Pediatrics, Emory Vaccine Center, Emory University, Atlanta, GA 30329, United States of America
| | - Zhaozhao Jiang
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, United States of America
| | - Ali A. Ashkar
- McMaster Immunology Research Centre, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- MG DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - George Thomas
- Department of of Internal Medicine, Division of Hematology/Oncology, University of Cincinnati Medical School, Cincinnati, 45267-0508 OH, United States of America
- Laboratory of Metabolism and Cancer, Catalan Institute of Oncology, ICO, Bellvitge Biomedical Research Institute, IDIBELL, 08908 Barcelona, Spain
- Departament Ciències Fisiològiques II, Facultat de Medicina, Universitat de Barcelona, 08908, Barcelona, Spain
| | - Sara C. Kozma
- Department of of Internal Medicine, Division of Hematology/Oncology, University of Cincinnati Medical School, Cincinnati, 45267-0508 OH, United States of America
- Laboratory of Metabolism and Cancer, Catalan Institute of Oncology, ICO, Bellvitge Biomedical Research Institute, IDIBELL, 08908 Barcelona, Spain
| | - Michael Gale
- Department of Immunology, University of Washington School of Medicine, Seattle, Washington, WA98195, United States of America
| | - Katherine A. Fitzgerald
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, United States of America
| | - Michael S. Diamond
- Department of Medicine, Molecular Microbiology, Pathology & Immunology, Washington, University School of Medicine, St Louis, MO 63110, United States of America
| | - Karen Mossman
- McMaster Immunology Research Centre, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- MG DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada
| | - Yonghong Wan
- McMaster Immunology Research Centre, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- MG DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Brian D. Lichty
- McMaster Immunology Research Centre, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- MG DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
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Chang GR, Chiu YS, Wu YY, Lin YC, Hou PH, Mao FC. Rapamycin impairs HPD-induced beneficial effects on glucose homeostasis. Br J Pharmacol 2015; 172:3793-804. [PMID: 25884889 PMCID: PMC4523336 DOI: 10.1111/bph.13168] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 03/08/2015] [Accepted: 04/07/2015] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND AND PURPOSE Rapamycin, which is used clinically to treat graft rejection, has also been proposed to have an effect on metabolic syndrome; however, very little information is available on its effects in lean animals/humans. The purpose of this study was to characterize further the effects of the continuous use of rapamycin on glucose homeostasis in lean C57BL6/J mice. EXPERIMENTAL APPROACH Mice were fed a high-protein diet (HPD) for 12 weeks to develop a lean model and then were treated daily with rapamycin for 5 weeks while remaining on a HPD. Metabolic parameters, endocrine profiles, glucose tolerance tests, insulin sensitivity index, the expression of the glucose transporter GLUT4 and chromium distribution were measured in vivo. KEY RESULTS Lower body weight gain as well as a decreased caloric intake, fat pads, fatty liver scores, adipocyte size and glucose tolerance test values were observed in HPD-fed mice compared with mice fed a high-fat or standard diet. Despite these beneficial effects, rapamycin-treated lean mice showed greater glucose intolerance, reduced insulin sensitivity, lower muscle GLUT4 expression and changes in chromium levels in tissues even with high insulin levels. CONCLUSION AND IMPLICATIONS Our findings demonstrate that continuous rapamycin administration may lead to the development of diabetes syndrome, as it was found to induce hyperglycaemia and glucose intolerance in a lean animal model.
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Affiliation(s)
- Geng-Ruei Chang
- Department of Veterinary Medicine, National Chung Hsing UniversityTaichung, Taiwan
- Division of Residual Control, Agricultural Chemicals and Toxic Substance Research Institute, Council of AgricultureTaichung, Taiwan
| | - Yi-Shin Chiu
- Department of Veterinary Medicine, National Chung Hsing UniversityTaichung, Taiwan
| | - Ying-Ying Wu
- Department of Veterinary Medicine, National Chung Hsing UniversityTaichung, Taiwan
| | - Yu-Chi Lin
- Department of Veterinary Medicine, National Chung Hsing UniversityTaichung, Taiwan
| | - Po-Hsun Hou
- Department of Veterinary Medicine, National Chung Hsing UniversityTaichung, Taiwan
- Department of Psychiatry, Taichung Veterans General HospitalTaichung, Taiwan
| | - Frank Chiahung Mao
- Department of Veterinary Medicine, National Chung Hsing UniversityTaichung, Taiwan
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The placental mTOR-pathway: correlation with early growth trajectories following intrauterine growth restriction? J Dev Orig Health Dis 2015; 6:317-26. [PMID: 25989725 DOI: 10.1017/s2040174415001154] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Idiopathic intrauterine growth restriction (IUGR) is a result of impaired placental nutrient supply. Newborns with IUGR exhibiting postnatal catch-up growth are of higher risk for cardiovascular and metabolic co-morbidities in adult life. Mammalian target of rapamycin (mTOR) was recently shown to function as a placental nutrient sensor. Thus, we determined possible correlations of members of the placental mTOR signaling cascade with auxologic parameters of postnatal growth. The protein expression and activity of mTOR-pathway signaling components, Akt, AMP-activated protein kinase α, mTOR, p70S6kinase1 and insulin receptor substrate-1 were analysed via western blotting in IUGR v. matched appropriate-for-gestational age (AGA) placentas. Moreover, mTOR was immunohistochemically stained in placental sections. Data from western blot analyses were correlated with retrospective auxological follow-up data at 1 year of age. We found significant catch-up growth in the 1st year of life in the IUGR group. MTOR and its activated form are immunohistochemically detected in multiple placental compartments. We identified correlations of placental mTOR-pathway signaling components to auxological data at birth and at 1 year of life in IUGR. Analysis of the protein expression and phosphorylation level of mTOR-pathway components in IUGR and AGA placentas postpartum, however, did not reveal pathognomonic changes. Our findings suggest that the level of activated mTOR correlates with early catch-up growth following IUGR. However, the complexity of signals converging at the mTOR nexus and its cellular distribution pattern seem to limit its potential as biomarker in this setting.
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16
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Soliman GA. The role of mechanistic target of rapamycin (mTOR) complexes signaling in the immune responses. Nutrients 2013; 5:2231-57. [PMID: 23783557 PMCID: PMC3725503 DOI: 10.3390/nu5062231] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 06/05/2013] [Accepted: 06/05/2013] [Indexed: 12/17/2022] Open
Abstract
The mechanistic Target of Rapamycin (mTOR) is an evolutionarily conserved serine/threonine kinase which is a member of the PI3K related kinase (PIKK) family. mTOR emerged as a central node in cellular metabolism, cell growth, and differentiation, as well as cancer metabolism. mTOR senses the nutrients, energy, insulin, growth factors, and environmental cues and transmits signals to downstream targets to effectuate the cellular and metabolic response. Recently, mTOR was also implicated in the regulation of both the innate and adaptive immune responses. This paper will summarize the current knowledge of mTOR, as related to the immune microenvironment and immune responses.
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Affiliation(s)
- Ghada A Soliman
- Department of Health Promotion, Social and Behavioral Health Sciences, College of Public Health, University of Nebraska Medical Center, 984365 Nebraska Medical Center, Omaha, NE 68198, USA.
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17
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Association of sirolimus adverse effects with m-TOR, p70S6K or Raptor polymorphisms in kidney transplant recipients. Pharmacogenet Genomics 2013; 22:725-32. [PMID: 22863900 DOI: 10.1097/fpc.0b013e328357359d] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND The mammalian target of rapamycin (m-TOR) inhibitor sirolimus is an immunosuppressive drug used in kidney transplantation. m-TOR binds with Raptor and phosphorylates p70S6 kinase, a protein involved in numerous cell signalling pathways. We examined the association of candidate polymorphisms in m-TOR, Raptor and p70S6K, sirolimus dose and exposure, and other time-independent as well as time-dependent covariates, with sirolimus-induced adverse events in kidney transplant recipients. METHODS This study included a first group of 113 patients, switched from a calcineurin inhibitor to sirolimus, and a validation group of 66 patients from another clinical trial, with the same immunosuppressive regimen. The effects of gene polymorphisms and covariates on the total cholesterol, LDL cholesterol, triglycerides, haemoglobin, cutaneous adverse events, oedemas and infections were studied using multilinear regression, or logistic regression imbedded in linear mixed-effect models. RESULTS An m-TOR variant haplotype was significantly associated with a decrease in haemoglobin levels in the two populations of patients (discovery group: β=-0.82 g/dl, P=0.0076; validation group: β=-1.58 g/dl, P=0.0308). Increased sirolimus trough levels were significantly associated with increased total cholesterol levels (discovery group: β=0.02 g/l, P<0.0001; validation group: β=0.02 g/l, P=0.0002) and triglyceride levels (discovery group: β=0.02 g/l, P=0.0059; validation group: β=0.05 g/l, P=0.0370). Sirolimus trough levels were also associated with an increased risk for cutaneous adverse events [odds ratio=1.97, 95% confidence interval (1.32-1.94), P=0.0009] and oedemas [odds ratio=1.16, 95% confidence interval (1.03-1.30), P=0.01342] in the discovery group, but this was not confirmed in the validation group. CONCLUSION These results provide evidence of an association between an m-TOR haplotype and a decrease in haemoglobin in renal transplant recipients.
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18
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mTOR regulates cellular iron homeostasis through tristetraprolin. Cell Metab 2012; 16:645-57. [PMID: 23102618 PMCID: PMC3594686 DOI: 10.1016/j.cmet.2012.10.001] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 08/13/2012] [Accepted: 10/04/2012] [Indexed: 12/12/2022]
Abstract
Iron is an essential cofactor with unique redox properties. Iron-regulatory proteins 1 and 2 (IRP1/2) have been established as important regulators of cellular iron homeostasis, but little is known about the role of other pathways in this process. Here we report that the mammalian target of rapamycin (mTOR) regulates iron homeostasis by modulating transferrin receptor 1 (TfR1) stability and altering cellular iron flux. Mechanistic studies identify tristetraprolin (TTP), a protein involved in anti-inflammatory response, as the downstream target of mTOR that binds to and enhances degradation of TfR1 mRNA. We also show that TTP is strongly induced by iron chelation, promotes downregulation of iron-requiring genes in both mammalian and yeast cells, and modulates survival in low-iron states. Taken together, our data uncover a link between metabolic, inflammatory, and iron-regulatory pathways, and point toward the existence of a yeast-like TTP-mediated iron conservation program in mammals.
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Braun S, Bitton-Worms K, LeRoith D. The link between the metabolic syndrome and cancer. Int J Biol Sci 2011; 7:1003-15. [PMID: 21912508 PMCID: PMC3164150 DOI: 10.7150/ijbs.7.1003] [Citation(s) in RCA: 181] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 07/24/2011] [Indexed: 01/08/2023] Open
Abstract
Since the incidence of the metabolic syndrome is on the rise in the western world, its coherence to cancer is becoming more apparent. In this review we discuss the different potential factors involved in the increase of cancer in the metabolic syndrome including obesity, dyslipidemia and Type 2 Diabetes Mellitus (T2DM) as well as inflammation and hypoxia. We especially focus on the insulin and IGF systems with their intracellular signaling cascades mediated by different receptor subtypes, and suggest that they may play major roles in this process. Understanding the mechanisms involved will be helpful in developing potential therapeutics.
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Affiliation(s)
- Sandra Braun
- Diabetes and Metabolism Clinical Research Center of Excellence, Legacy Heritage Clinical Research Institute at Rambam (LHCRIR), Haifa, Israel
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20
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The Role of mTOR Inhibitors for the Treatment of B-Cell Lymphomas. Adv Hematol 2011; 2012:435342. [PMID: 21822434 PMCID: PMC3124126 DOI: 10.1155/2012/435342] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 04/07/2011] [Indexed: 02/02/2023] Open
Abstract
Despite the fact that the majority of lymphomas initially respond to treatment, many patients relapse and die from disease that is refractory to current regimens. The need for new treatment strategies in lymphomas has led to the investigation and evaluation of novel agents that target cellular pathways. The mammalian target of rapamycin (mTOR) is a representative pathway that may be implicated in lymphomagenesis. Rapamycin and especially its derivatives (temsirolimus, everolimus, and deforolimus) represent the first described mTOR inhibitors. These agents have shown promising results in the treatment of lymphoid malignancies. On the other hand, new ATP-competitive mTOR inhibitors that provoke a broader inhibition of mTOR activity are in early stages of clinical development. The purpose of this paper is to summarize the existing knowledge about mTOR inhibitors and their use in the treatment of B-cell lymphomas. Relevant issues regarding mTOR biology in general as well as in B-cell lymphoid neoplasms are also discussed in short.
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21
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Sun M, Si L, Zhai X, Fan Z, Ma Y, Zhang R, Yang X. The influence of co-solvents on the stability and bioavailability of rapamycin formulated in self-microemulsifying drug delivery systems. Drug Dev Ind Pharm 2011; 37:986-94. [DOI: 10.3109/03639045.2011.553618] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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22
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Goff SA. A unifying theory for general multigenic heterosis: energy efficiency, protein metabolism, and implications for molecular breeding. THE NEW PHYTOLOGIST 2011; 189:923-937. [PMID: 21166808 DOI: 10.1111/j.1469-8137.2010.03574.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Hybrids between genetically diverse varieties display enhanced growth, and increased total biomass, stress resistance and grain yield. Gene expression and metabolic studies in maize, rice and other species suggest that protein metabolism plays a role in the growth differences between hybrids and inbreds. Single trait heterosis can be explained by the existing theories of dominance, overdominance and epistasis. General multigenic heterosis is observed in a wide variety of different species and is likely to share a common underlying biological mechanism. This review presents a model to explain differences in growth and yield caused by general multigenic heterosis. The model describes multigenic heterosis in terms of energy-use efficiency and faster cell cycle progression where hybrids have more efficient growth than inbreds because of differences in protein metabolism. The proposed model is consistent with the observed variation of gene expression in different pairs of inbred lines and hybrid offspring as well as growth differences in polyploids and aneuploids. It also suggests an approach to enhance yield gains in both hybrid and inbred crops via the creation of an appropriate computational analysis pipeline coupled to an efficient molecular breeding program.
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Affiliation(s)
- Stephen A Goff
- iPlant Collaborative, BIO5 Institute, University of Arizona, Tucson, AZ 85721, USA
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23
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Soliman GA, Acosta-Jaquez HA, Fingar DC. mTORC1 inhibition via rapamycin promotes triacylglycerol lipolysis and release of free fatty acids in 3T3-L1 adipocytes. Lipids 2010; 45:1089-100. [PMID: 21042876 DOI: 10.1007/s11745-010-3488-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Accepted: 10/07/2010] [Indexed: 12/30/2022]
Abstract
Signaling by mTOR complex 1 (mTORC1) promotes anabolic cellular processes in response to growth factors, nutrients, and hormonal cues. Numerous clinical trials employing the mTORC1 inhibitor rapamycin (aka sirolimus) to immuno-suppress patients following organ transplantation have documented the development of hypertriglyceridemia and elevated serum free fatty acids (FFA). We therefore investigated the cellular role of mTORC1 in control of triacylglycerol (TAG) metabolism using cultured murine 3T3-L1 adipocytes. We found that treatment of adipocytes with rapamycin reduced insulin-stimulated TAG storage ~50%. To determine whether rapamycin reduces TAG storage by upregulating lipolytic rate, we treated adipocytes in the absence and presence of rapamycin and isoproterenol, a β2-adrenergic agonist that activates the cAMP/protein kinase A (PKA) pathway to promote lipolysis. We found that rapamycin augmented isoproterenol-induced lipolysis without altering cAMP levels. Rapamycin enhanced the isoproterenol-stimulated phosphorylation of hormone sensitive lipase (HSL) on Ser-563 (a PKA site), but had no effect on the phosphorylation of HSL S565 (an AMPK site). Additionally, rapamycin did not affect the isoproterenol-mediated phosphorylation of perilipin, a protein that coats the lipid droplet to initiate lipolysis upon phosphorylation by PKA. These data demonstrate that inhibition of mTORC1 signaling synergizes with the β-adrenergic-cAMP/PKA pathway to augment phosphorylation of HSL to promote hormone-induced lipolysis. Moreover, they reveal a novel metabolic function for mTORC1; mTORC1 signaling suppresses lipolysis, thus augmenting TAG storage.
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Affiliation(s)
- Ghada A Soliman
- Division of Metabolism, Endocrinology, and Diabetes, Department of Medicine, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA.
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Argyriou P, Papageorgiou SG, Panteleon V, Psyrri A, Bakou V, Pappa V, Spathis A, Economopoulou P, Papageorgiou E, Economopoulos T, Rontogianni D. Hypoxia-inducible factors in mantle cell lymphoma: implication for an activated mTORC1→HIF-1α pathway. Ann Hematol 2010; 90:315-22. [DOI: 10.1007/s00277-010-1070-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Accepted: 08/25/2010] [Indexed: 12/21/2022]
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25
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Keller JN. Interplay between oxidative damage, protein synthesis, and protein degradation in Alzheimer's disease. J Biomed Biotechnol 2010; 2006:12129. [PMID: 17047298 PMCID: PMC1510934 DOI: 10.1155/jbb/2006/12129] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Protein synthesis and protein degradation are highly regulated
cellular processes that are essential to maintaining cell
viability. Numerous studies now indicate that protein synthesis
and protein degradation are significantly altered in Alzheimer's
disease (AD), with impairments in these two processes potentially
contributing to AD pathogenesis. Alterations in steady state
protein regulation may be a particularly important factor in
regulating whether cells maintain homeostasis in response to
oxidative damage, or conversely whether oxidative stress is
induced by oxidative damage. The focus of this review is to
discuss recent findings on each of these topics, and to discuss
their importance to the onset and progression of AD.
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Affiliation(s)
- Jeffrey N Keller
- Anatomy and Neurobiology, Sanders Brown Center on Aging, University of Kentucky, Lexington, KY 40536, USA
- *Jeffrey N. Keller:
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26
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Chang GR, Wu YY, Chiu YS, Chen WY, Liao JW, Hsu HM, Chao TH, Hung SW, Mao FC. Long-term Administration of Rapamycin Reduces Adiposity, but Impairs Glucose Tolerance in High-Fat Diet-fed KK/HlJ Mice. Basic Clin Pharmacol Toxicol 2009; 105:188-98. [DOI: 10.1111/j.1742-7843.2009.00427.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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27
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Chang GR, Chiu YS, Wu YY, Chen WY, Liao JW, Chao TH, Mao FC. Rapamycin protects against high fat diet-induced obesity in C57BL/6J mice. J Pharmacol Sci 2009; 109:496-503. [PMID: 19372632 DOI: 10.1254/jphs.08215fp] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Rapamycin (RAPA), an immunosuprpressive drug used extensively to prevent graft rejection in transplant patients, has been reported to inhibit adipogenesis in vitro. In this study, we investigated the anti-obesity effects of RAPA in C57BL/6J mice on a high-fat diet (HFD). Mice treated with RAPA (2 mg/kg per week for 16 weeks) had reduced body weight and epididymal fat pads/body weight, reduced daily food efficiency, and lower serum leptin and insulin levels compared with the HFD control mice. However, RAPA-treated mice were hyperphagic, demonstrating an increase in food intake. Dissection of RAPA-treated mice revealed a marked reduction in fatty liver scores, average fat cell size, and percentage of large adipocytes of retroperitoneal and epididymal white adipose tissue (RWAT and EWAT), compared to the HFD control mice. These results suggest that RAPA prevented the effect of the high-fat diet on the rate of accretion in body weight via reducing lipid accumulation, despite greater food intake. It is likely that RAPA may serve as a potential strategy for body weight control and/or anti-obesity therapy.
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Affiliation(s)
- Geng-Ruei Chang
- Department of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
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28
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Xu G, Xia J, Hua X, Zhou H, Yu C, Liu Z, Cai K, Shi J, Li H. Activated mammalian target of rapamycin is associated with T regulatory cell insufficiency in nasal polyps. Respir Res 2009; 10:13. [PMID: 19250527 PMCID: PMC2651851 DOI: 10.1186/1465-9921-10-13] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Accepted: 02/27/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Decreased infiltration of Foxp3+ T regulatory cell (Treg) is considered to be critical for the Th1/Th2 dysregulation of nasal polyps, while the cellular mechanism underlying Foxp3+ Treg insufficiency is currently not well defined. METHODS We attempted to investigate the tissue expression of phosphorylated mammalian target of rapamycin (pmTOR) and infiltration of Foxp3+ Tregs in 28 nasal polyps and 16 controls by histological staining. We also evaluated the effects of blocking the mTOR signaling pathway with rapamycin on T cell phenotype selection and Foxp3+CD4+ Tregs expansion in a tissue culture system. RESULTS Significantly increased infiltration of pmTOR+ inflammatory cells and decreased infiltration of Foxp3+CD4+ Tregs into nasal polyps was observed, with an inverse association. In the tissue culture system, we detected significantly elevated Foxp3 expression and IL-10 production, as well as an increased percentage of Foxp3+ Tregs in nasal polyps after blocking the mTOR signaling pathway with rapamycin. CONCLUSION Here we demonstrate for the first time that the mTOR signaling pathway is associated with Foxp3+ Tregs insufficiency in nasal polyps. Inhibition of the mTOR signaling pathway may be helpful for enhancement of Foxp3+ Treg expansion, as well as modulation of T cell phenotype imbalances in nasal polyps.
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Affiliation(s)
- Geng Xu
- Allergy and Cancer Center, Otorhinolaryngology Hospital of the First Affiliated Hospital of Sun Yat-sen University, and Otorhinolaryngology Institute of Sun Yat-sen University, Guangzhou, PR China
| | - Jiahong Xia
- Department of Surgery, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China
| | - Xiaoyang Hua
- Department of Surgery, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China
| | - Han Zhou
- Department of Otolaryngology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, PR China
| | - Chuanzhao Yu
- Department of Otolaryngology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, PR China
| | - Zheng Liu
- Department of Surgery, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China
| | - Kemin Cai
- Department of Otolaryngology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, PR China
| | - Jianbo Shi
- Allergy and Cancer Center, Otorhinolaryngology Hospital of the First Affiliated Hospital of Sun Yat-sen University, and Otorhinolaryngology Institute of Sun Yat-sen University, Guangzhou, PR China
| | - Huabin Li
- Allergy and Cancer Center, Otorhinolaryngology Hospital of the First Affiliated Hospital of Sun Yat-sen University, and Otorhinolaryngology Institute of Sun Yat-sen University, Guangzhou, PR China
- Department of Otolaryngology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, PR China
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Investigation of the regulation of transcriptional changes in Ancylostoma caninum larvae following serum activation, with a focus on the insulin-like signalling pathway. Vet Parasitol 2008; 159:139-48. [PMID: 19054616 DOI: 10.1016/j.vetpar.2008.10.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2008] [Revised: 09/30/2008] [Accepted: 10/09/2008] [Indexed: 12/23/2022]
Abstract
The exit from dauer in the free-living nematode Caenorhabditis elegans is under the control of a single amphidial neuron (ASJ) of the insulin-like signalling pathway. Mutations of this pathway have the ability to suppress entry into the dauer stage. It has been postulated that insulin-like signalling plays a significant role in the response to serum stimulation in vitro of the third-stage larvae (L3s) of the canine hookworm Ancylostoma caninum. To test for the possible involvement of the insulin-like signalling cascade in the response to serum stimulation, the effects of two signalling stimulants (8-bromo cGMP and arecoline) and four inhibitors, namely 4,7-phenanthroline, phosphoinositide-3 kinase (PI3K), Akt inhibitor IV and rapamycin on feeding and on levels of selected activation-associated mRNAs in serum-stimulated L3s were explored. L3s of A. caninum were pre-incubated with or without the appropriate inhibitor/agonist. Following serum-stimulation, the feeding activity was assessed. The transcription levels of a number of activation-associated mRNAs linked to particular expressed sequence tags (ESTs) were investigated by reverse transcription, real-time PCR (rtPCR). The treatment of worms with 4,7-phenanthroline completely suppressed feeding and significantly reduced the differential levels of most activation-associated mRNAs, whereas the treatment with cGMP resulted in the resumption of feeding in almost 85% of the L3s and yielded a specific transcriptional profile consistent with that following serum stimulation. The treatment of L3s with arecoline resulted in the resumption of feeding in approximately 85% of L3s, but did not result in a transcriptomic profile consistent with activation. A complete reduction in feeding was recorded in the presence of the PI3K inhibitor LY294002 (1mM) and resulted in a pronounced dampening of differential transcription in response to serum stimulation for the molecules examined. Akt inhibitor IV resulted in a approximately 70% reduction in feeding but had almost no effect on the level of any of the activation-associated mRNAs studied. Rapamycin was shown to have a weak effect on feeding, and several of the mRNAs studied exhibited greater than expected transcription following treatment. The complexities of activation-associated transcription could not be addressed using the current approach. A larger number of mRNAs needs to be investigated in order to predict or identify regulatory mechanisms proposed to function in the insulin-like signalling pathway in A. caninum.
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Budanov AV, Karin M. p53 target genes sestrin1 and sestrin2 connect genotoxic stress and mTOR signaling. Cell 2008; 134:451-60. [PMID: 18692468 DOI: 10.1016/j.cell.2008.06.028] [Citation(s) in RCA: 1033] [Impact Index Per Article: 64.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2007] [Revised: 01/25/2008] [Accepted: 06/09/2008] [Indexed: 12/17/2022]
Abstract
The tumor suppressor p53 is activated upon genotoxic and oxidative stress and in turn inhibits cell proliferation and growth through induction of specific target genes. Cell growth is positively regulated by mTOR, whose activity is inhibited by the TSC1:TSC2 complex. Although genotoxic stress has been suggested to inhibit mTOR via p53-mediated activation of mTOR inhibitors, the precise mechanism of this link was unknown. We now demonstrate that the products of two p53 target genes, Sestrin1 and Sestrin2, activate the AMP-responsive protein kinase (AMPK) and target it to phosphorylate TSC2 and stimulate its GAP activity, thereby inhibiting mTOR. Correspondingly, Sestrin2-deficient mice fail to inhibit mTOR signaling upon genotoxic challenge. Sestrin1 and Sestrin2 therefore provide an important link between genotoxic stress, p53 and the mTOR signaling pathway.
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Affiliation(s)
- Andrei V Budanov
- Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology, School of Medicine, University of California, San Diego, 9500 Gilman Drive, MC0723, La Jolla, CA 92093, USA
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Lian J, Yan XH, Peng J, Jiang SW. The mammalian target of rapamycin pathway and its role in molecular nutrition regulation. Mol Nutr Food Res 2008; 52:393-9. [PMID: 18306429 DOI: 10.1002/mnfr.200700005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Mammalian target of rapamycin (mTOR) is a protein serine-threonine kinase that functions as a central element in signaling pathway involved in control of cell growth and proliferation. mTOR exists in at least two distinct multi-protein complexes, mTORC1 and mTORC2. mTOR kinase controls the translation machinery, in response to nutrients and growth factors, via activation of p70 ribosomal S6 kinase and inhibition of eukaryotic initiation factor-4E-binding protein. In this report, we review the mTOR signaling pathway and its interaction with food intake, insulin resistance, lifespan and adipogenic regulation during the molecular nutrition regulation.
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Affiliation(s)
- Jun Lian
- Laboratory of Animal Molecular Nutrition, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, P.R. China
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Mammalian target of rapamycin and glycogen synthase kinase 3 differentially regulate lipopolysaccharide-induced interleukin-12 production in dendritic cells. Blood 2008; 112:635-43. [PMID: 18492954 DOI: 10.1182/blood-2008-02-137430] [Citation(s) in RCA: 204] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Phosphoinositide 3-kinase (PI3K) negatively regulates Toll-like receptor (TLR)-mediated interleukin-12 (IL-12) expression in dendritic cells (DCs). We show here that 2 signaling pathways downstream of PI3K, mammalian target of rapamycin (mTOR) and glycogen synthase kinase 3 (GSK3), differentially regulate the expression of IL-12 in lipopolysaccharide (LPS)-stimulated DCs. Rapamycin, an inhibitor of mTOR, enhanced IL-12 production in LPS-stimulated DCs, whereas the activation of mTOR by lentivirus-mediated transduction of a constitutively active form of Rheb suppressed the production of IL-12. The inhibition of protein secretion or deletion of IL-10 cancelled the effect of rapamycin, indicating that mTOR regulates IL-12 expression through an autocrine action of IL-10. In contrast, GSK3 positively regulates IL-12 production through an IL-10-independent pathway. Rapamycin-treated DCs enhanced Th1 induction in vitro compared with untreated DCs. LiCl, an inhibitor of GSK3, suppressed a Th1 response on Leishmania major infection in vivo. These results suggest that mTOR and GSK3 pathways regulate the Th1/Th2 balance though the regulation of IL-12 expression in DCs. The signaling pathway downstream of PI3K would be a good target to modulate the Th1/Th2 balance in immune responses in vivo.
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Effects of rapamycin on gene expression, morphology, and electrophysiological properties of rat hippocampal neurons. Epilepsy Res 2007; 77:85-92. [PMID: 17983731 DOI: 10.1016/j.eplepsyres.2007.09.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Revised: 09/10/2007] [Accepted: 09/12/2007] [Indexed: 01/26/2023]
Abstract
PURPOSE We assayed the effects of rapamycin, an immunomodulatory agent known to inhibit the activity of the mammalian target of rapamycin (mTOR) cascade, on candidate gene expression and single unit firing properties in cultured rat hippocampal neurons as a strategy to define the effects of rapamycin on neuronal gene transcription and excitability. METHODS Rapamycin was added (100nM) to cultured hippocampal neurons on days 3 and 14. Neuronal somatic size and dendritic length were assayed by immunohistochemistry and digital imaging. Radiolabeled mRNA was amplified from single hippocampal pyramidal neurons and used to probe cDNA arrays containing over 100 distinct candidate genes including cytoskeletal element, growth factor, transcription factor, neurotransmitter, and ion channel genes. In addition, the effects of rapamycin (200nM) on spontaneous neuronal activity and voltage-dependent currents were assessed. RESULTS There were no effects of rapamycin on cell size or dendrite length. Rapamycin altered expression of distinct mRNAs in each gene family on days 3 and 14 in culture. Single unit recordings from neurons exposed to rapamycin exhibited no change from baseline. When spontaneous activity was increased by blocking GABA-mediated inhibition with bicuculline, a fraction of the neurons exhibited a decreased duration of spontaneous bursts and a decrease in synaptic inputs. Rapamycin did not appear to alter voltage-dependent Na(+) or K(+) currents underlying action potentials. CONCLUSIONS These data demonstrate that rapamycin does not produce neurotoxicity nor alter dendritic growth and complexity in vitro and does not significantly alter voltage-gated sodium and potassium currents. Rapamycin does affect neuronal gene transcription in vitro. Use of rapamycin in clinical trials for patients with tuberous sclerosis complex warrants vigilance for possible effects on seizure frequency and neurocognitive function.
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Husain SZ, Grant WM, Gorelick FS, Nathanson MH, Shah AU. Caerulein-induced intracellular pancreatic zymogen activation is dependent on calcineurin. Am J Physiol Gastrointest Liver Physiol 2007; 292:G1594-9. [PMID: 17332472 DOI: 10.1152/ajpgi.00500.2006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Aberrant cytosolic Ca(2+) flux in pancreatic acinar cells is critical to the pathological pancreatic zymogen activation observed in acute pancreatitis, but the downstream effectors are not known. In this study, we examined the role of Ca(2+)-activated protein phosphatase 2B (or calcineurin) in zymogen activation. Isolated pancreatic acinar cells were stimulated with supraphysiological caerulein (100 nM) with or without the calcineurin inhibitors FK506 or cell-permeable calcineurin inhibitory peptide (CiP). Chymotrypsin activity was measured as a marker of zymogen activation, and the percent amylase secretion was used as a measure of enzyme secretion. Cytosolic Ca(2+) changes were recorded in acinar cells loaded with the intermediate Ca(2+)-affinity dye fluo-5F using a scanning confocal microscope. A 50% reduction in chymotrypsin activity was observed after pretreatment with 1 microM FK506 or 10 microM CiP. These pretreatments did not affect amylase secretion or the rise in cytosolic Ca(2+) after caerulein stimulation. These findings suggest that calcineurin mediates caerulein-induced intra-acinar zymogen activation but not enzyme secretion or the initial caerulein-induced cytosolic Ca(2+) signal.
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Affiliation(s)
- Sohail Z Husain
- Dept. of Pediatrics, 333 Cedar St., FMP408, PO Box 208064, New Haven, CT 06520, USA.
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Roos S, Jansson N, Palmberg I, Säljö K, Powell TL, Jansson T. Mammalian target of rapamycin in the human placenta regulates leucine transport and is down-regulated in restricted fetal growth. J Physiol 2007; 582:449-59. [PMID: 17463046 PMCID: PMC2075295 DOI: 10.1113/jphysiol.2007.129676] [Citation(s) in RCA: 200] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Pathological fetal growth is associated with perinatal morbidity and the development of diabetes and cardiovascular disease later in life. Placental nutrient transport is a primary determinant of fetal growth. In human intrauterine growth restriction (IUGR) the activity of key placental amino acid transporters, such as systems A and L, is decreased. However the mechanisms regulating placental nutrient transporters are poorly understood. We tested the hypothesis that the mammalian target of rapamycin (mTOR) signalling pathway regulates amino acid transport in the human placenta and that the activity of the placental mTOR pathway is reduced in IUGR. Using immunohistochemistry and culture of trophoblast cells, we show for the first time that the mTOR protein is expressed in the transporting epithelium of the human placenta. We further demonstrate that placental mTOR regulates activity of the l-amino acid transporter, but not system A or taurine transporters, by determining the mediated uptake of isotope-labelled leucine, methylaminoisobutyric acid and taurine in primary villous fragments after inhibition of mTOR using rapamycin. The protein expression of placental phospho-S6K1 (Thr-389), a measure of the activity of the mTOR signalling pathway, was markedly reduced in placentas obtained from pregnancies complicated by IUGR. These data identify mTOR as an important regulator of placental amino acid transport, and provide a mechanism for the changes in placental leucine transport in IUGR previously demonstrated in humans. We propose that mTOR functions as a placental nutrient sensor, matching fetal growth with maternal nutrient availability by regulating placental nutrient transport.
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Affiliation(s)
- Sara Roos
- Perinatal Center, Department of Physiology, Institute of Neuroscience and Physiology, University of Gothenburg, PO Box 432, SE-405 30 Gothenburg, Sweden.
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Tate JJ, Cooper TG. Stress-responsive Gln3 localization in Saccharomyces cerevisiae is separable from and can overwhelm nitrogen source regulation. J Biol Chem 2007; 282:18467-18480. [PMID: 17439949 PMCID: PMC2269007 DOI: 10.1074/jbc.m609550200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Intracellular localization of Saccharomyces cerevisiae GATA family transcription activator, Gln3, is used as a downstream readout of rapamycin-inhibited Tor1,2 control of Tap42 and Sit4 activities. Gln3 is cytoplasmic in cells provided with repressive nitrogen sources such as glutamine and is nuclear in cells growing with a derepressive nitrogen source such as proline or those treated with rapamycin or methionine sulfoximine (Msx). Although gross Gln3-Myc13 phosphorylation levels in wild type cells do not correlate with nitrogen source-determined intracellular Gln3-Myc13 localization, the phosphorylation levels are markedly influenced by several environmental perturbations. Msx treatment increases Snf1-independent Gln3-Myc13 phosphorylation, whereas carbon starvation increases both Snf1-dependent and -independent Gln3-Myc13 phosphorylation. Here we demonstrate that a broad spectrum of environmental stresses (temperature, osmotic, and oxidative) increase Gln3-Myc13 phosphorylation. In parallel, these stresses elicit rapid (<5 min for NaCl) Gln3-Myc13 relocalization from the nucleus to the cytoplasm. The response of Gln3-Myc13 localization to stressful conditions can completely overwhelm its response to nitrogen source quality or inhibitor-generated disruption of the Tor1,2 signal transduction pathway. Adding NaCl to cells cultured under conditions in which Gln3-Myc13 is normally nuclear, i.e. proline-grown, nitrogen-starved, Msx-, caffeine-, and rapamycin-treated wild type cells, or ure2Delta cells, results in its prompt relocalization to the cytoplasm. Together these data identify a major new level of regulation to which Gln3 responds, and adds a new dimension to mechanistic studies of the regulation of this transcription factor.
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Affiliation(s)
- Jennifer J Tate
- Department of Molecular Sciences, University of Tennessee, Memphis, Tennessee 38163
| | - Terrance G Cooper
- Department of Molecular Sciences, University of Tennessee, Memphis, Tennessee 38163.
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Bogush A, Pedrini S, Pelta-Heller J, Chan T, Yang Q, Mao Z, Sluzas E, Gieringer T, Ehrlich ME. AKT and CDK5/p35 Mediate Brain-derived Neurotrophic Factor Induction of DARPP-32 in Medium Size Spiny Neurons in Vitro. J Biol Chem 2007; 282:7352-9. [PMID: 17209049 DOI: 10.1074/jbc.m606508200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mature striatal medium size spiny neurons express the dopamine and cyclic AMP-regulated phosphoprotein, 32 kDa (DARPP-32), but little is known about the mechanisms regulating its levels or the specification of fully differentiated neuronal subtypes. Cell extrinsic molecules that increase DARPP-32 mRNA and/or protein levels include brain-derived neurotrophic factor (BDNF), retinoic acid, and estrogen. DARPP-32 induction by BDNF in vitro requires phosphatidylinositide 3-kinase (PI3K), but inhibition of phosphorylation of protein kinase B/Akt does not entirely abolish expression of DARPP-32. Moreover, the requirement for Akt has not been established. Using pharmacologic inhibitors of PI3K, Akt, and cyclin-dependent kinase 5 (cdk5) and constitutively active and dominant negative PI3K, Akt, cdk5, and p35 viruses in cultured striatal neurons, we measured BDNF-induced levels of DARPP-32 protein and/or mRNA. We demonstrated that both the PI3K/Akt/mammalian target of rapamycin and the cdk5/p35 signal transduction pathways contribute to the induction of DARPP-32 protein levels by BDNF and that the effects are on both the transcriptional and translational levels. It also appears that PI3K is upstream of cdk5/p35, and its activation can lead to an increase in p35 protein levels. These data support the presence of multiple signal transduction pathways mediating expression of DARPP-32 in vitro, including a novel, important pathway via by which PI3K regulates the contribution of cdk5/p35.
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Affiliation(s)
- Alexey Bogush
- Farber Institute for Neurosciences and Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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Morcuende R, Bari R, Gibon Y, Zheng W, Pant BD, Bläsing O, Usadel B, Czechowski T, Udvardi MK, Stitt M, Scheible WR. Genome-wide reprogramming of metabolism and regulatory networks of Arabidopsis in response to phosphorus. PLANT, CELL & ENVIRONMENT 2007; 30:85-112. [PMID: 17177879 DOI: 10.1111/j.1365-3040.2006.01608.x] [Citation(s) in RCA: 348] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Affymetrix ATH1 arrays, large-scale real-time reverse transcription PCR of approximately 2200 transcription factor genes and other gene families, and analyses of metabolites and enzyme activities were used to investigate the response of Arabidopsis to phosphate (Pi) deprivation and re-supply. Transcript data were analysed with MapMan software to identify coordinated, system-wide changes in metabolism and other cellular processes. Phosphorus (P) deprivation led to induction or repression of > 1000 genes involved in many processes. A subset, including the induction of genes involved in P uptake, the mobilization of organic Pi, the conversion of phosphorylated glycolytic intermediates to carbohydrates and organic acids, the replacement of P-containing phospholipids with galactolipids and the repression of genes involved in nucleotide/nucleic acid synthesis, was reversed within 3 h after Pi re-supply. Analyses of 22 enzyme activities revealed that changes in transcript levels often, but not always, led to changes in the activities of the encoded enzymes in P-deprived plants. Analyses of metabolites confirmed that P deprivation leads to a shift towards the accumulation of carbohydrates, organic acids and amino acids, and that Pi re-supply leads to use of the latter. P-deprived plants also showed large changes in the expression of many genes involved in, for example, secondary metabolism and photosynthesis. These changes were not reversed rapidly upon Pi re-supply and were probably secondary in origin. Differentially expressed and highly P-specific putative regulator genes were identified that presumably play central roles in coordinating the complex responses of plants to changes in P nutrition. The specific responses to Pi differ markedly from those found for nitrate, whereas the long-term responses during P and N deprivation share common and non-specific features.
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Affiliation(s)
- Rosa Morcuende
- Max-Planck Institute for Molecular Plant Physiology, Science Park Golm, 14476 Potsdam, Germany
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Marshall S. Role of insulin, adipocyte hormones, and nutrient-sensing pathways in regulating fuel metabolism and energy homeostasis: a nutritional perspective of diabetes, obesity, and cancer. ACTA ACUST UNITED AC 2006; 2006:re7. [PMID: 16885148 DOI: 10.1126/stke.3462006re7] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Traditionally, nutrients such as glucose and amino acids have been viewed as substrates for the generation of high-energy molecules and as precursors for the biosynthesis of macromolecules. However, it is now apparent that nutrients also function as signaling molecules in functionally diverse signal transduction pathways. Glucose and amino acids trigger signaling cascades that regulate various aspects of fuel and energy metabolism and control the growth, proliferation, and survival of cells. Here, we provide a functional and regulatory overview of three well-established nutrient signaling pathways-the hexosamine signaling pathway, the mTOR (mammalian target of rapamycin) signaling pathway, and the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway. Nutrient signaling pathways are interconnected, coupled to insulin signaling, and linked to the release of metabolic hormones from adipose tissue. Thus, nutrient signaling pathways do not function in isolation. Rather, they appear to serve as components of a larger "metabolic regulatory network" that controls fuel and energy metabolism (at the cell, tissue, and whole-body levels) and links nutrient availability with cell growth and proliferation. Understanding the diverse roles of nutrients and delineating nutrient signaling pathways should facilitate drug discovery research and the search for novel therapeutic compounds to prevent and treat various human diseases such as diabetes, obesity, and cancer.
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Aggarwal D, Fernandez ML, Soliman GA. Rapamycin, an mTOR inhibitor, disrupts triglyceride metabolism in guinea pigs. Metabolism 2006; 55:794-802. [PMID: 16713440 DOI: 10.1016/j.metabol.2006.01.017] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2005] [Accepted: 01/30/2006] [Indexed: 12/29/2022]
Abstract
This study was designed to define some of the mechanisms by which rapamycin (RAPA), an mTOR inhibitor, induces hypertriglyceridemia when used as an immunosuppressive or antiproliferative agent and to determine whether low doses result in less undesirable side effects. Thirty male guinea pigs (n=10 per group) were randomly assigned to control (no RAPA), low-RAPA (0.08 mg/d), or high-RAPA (0.85 mg/d) treatment for 3 weeks. Rapamycin treatment resulted in more than a 2-fold increase in plasma triglycerides (TG) (P<.01), whereas no differences were observed in plasma cholesterol between RAPA and control groups. Low-RAPA treatment resulted in lower concentrations of cholesterol in the aorta (28.6%) and lower hepatic acyl-CoA cholesteryl acyltransferase activity compared to control and high-RAPA groups (P<.01). In addition, acyl-CoA cholesteryl acyltransferase activity was positively correlated with aortic cholesterol (r=0.43, P<.05). In contrast, aortic TG concentrations were higher in RAPA-treated guinea pigs than in control (P<.01). Very low density lipoprotein and low-density lipoprotein particles isolated from guinea pigs treated with RAPA were larger in size and contained more TG molecules than particles from control animals. Interestingly, plasma free fatty acids and fasting plasma glucose were 65% and 72% higher in the high-RAPA group than in control (P<.01). Tumor necrosis factor-alpha concentrations in the aorta were 3.6- and 10.4-fold higher in the low-RAPA and high-RAPA groups than in control guinea pigs (P<.01). These results suggest that RAPA interferes with TG metabolism by altering the insulin signaling pathway, inducing increased secretion of very low density lipoprotein and promoting deposition of TG in the aorta. Low RAPA was found to decrease cholesterol accumulation in tissue (liver and aorta) compared to high RAPA, suggesting that lower doses could be less detrimental to transplant patients.
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Affiliation(s)
- Dimple Aggarwal
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269, USA
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